The recently observed regenerative capacity of the olfactory receptor neurons will be exploited to study phenomena related to the olfactory coding. By means of anatomical, electrophysiological and behavioral techniques we propose to study the olfactory mucosa, nerve and bulb system in normal pigeons and in pigeons where the olfactory nerves have been unilaterally or bilaterally out. Recent evidence in our laboratory indicates that regeneration occurs in the olfactory mucosa of pigeons following section of the olfactory nerve and that the regenerating neurons reestablish contacts with the bulb. Both structure and function are "normal" after a few weeks. The gradual recovery of the anatomical, electrophysiological and behavioral parameters in the system indicates that useful information could be gained in regard to the anatomical and electrophysiological requirements for the behavior in this animal.